Homogeneous linewidth broadening and exciton dephasing mechanism in MoTe2
Homogeneous linewidth broadening and exciton dephasing mechanism in MoTe2
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DOI：
10.1103/physrevb.93.075411
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发表时间：
2016-02-04
影响因子：
3.7
通讯作者：
Matsuda, Kazunari
中科院分区：
文献类型：
--
作者：
Koirala, Sandhaya;Mouri, Shinichiro;Matsuda, Kazunari
在4.2 ~ 300 K的较宽温度范围内对机械剥离的MoTe 2单层膜进行了光谱研究。在低温下，单层MoTe 2的光致发光光谱显示出两个尖锐的峰的激子和带电激子（trions）。激子峰的均匀线宽随温度的升高而线性展宽。这种线性线宽加宽是由激子的声学-声子散射引起的，即，激子失相的缩短。由于激子-声学-声子相互作用的加宽因子被发现是0.11毫电子伏K-1。激子-声子耦合系数的这个小的值和斯托克斯位移的缺乏表明，激子-声子相互作用在单层MoTe 2的弱耦合制度。
Spectroscopic studies of mechanically exfoliated monolayer MoTe2 were performed over a wide temperature range from 4.2 to 300 K. At a low temperature, the photoluminescence spectra for monolayer MoTe2 showed two sharp peaks for excitons and charged excitons (trions). The homogeneous linewidth of the exciton peak broadened linearly as the temperature increased. This linear linewidth broadening was caused by acoustic-phonon scattering of the exciton, i.e., shortening of exciton dephasing. The broadening factor due to exciton-acoustic-phonon interactions was found to be 0.11 meV K-1. This small value for the exciton-phonon coupling coefficient and the lack of a Stokes shift suggest that exciton-phonon interactions in monolayer MoTe2 are in the weak coupling regime.